Timeout budget for one transfer attempt — .p990

R's timeout option is a budget for the whole transfer, not an idle timeout: utils::download.file() aborts once it elapses even while bytes are still arriving. A fixed value therefore imposes a minimum transfer rate that rises with file size – 3.6 GB in 1800 seconds demands a sustained 2 MB/s. Where the size is known, convert it into the time it needs at .P990_MIN_RATE and keep whichever budget is larger.

Usage

.p990_timeout(timeout, bytes = NA_real_, floor = NULL)

Arguments

timeout: Requested per-attempt timeout in seconds.
bytes: Expected transfer size in bytes, or NA.
floor: A timeout already in force that must not be reduced.

Value

A length-one integer number of seconds.

Details

floor preserves a timeout the user raised globally, through options(timeout =) or the R_DEFAULT_INTERNET_TIMEOUT environment variable; ?download.file asks packages not to lower it.